Strange one this. Having first appeared on 2007's Blackout, 'Radar' was supposed to become its final single the following summer, but the release was scrapped when Britney returned to the recording studio sooner than expected. However, someone at Team Spears is clearly a fan of the track, because it managed to find its way onto last year's Circus album too.

And the story doesn't end there! Now, a whopping 21 months after it first caressed our ears, 'Radar' is being released as the final single from Circus. It still sounds pretty ace, one of the best examples of the robopop sound Blackout essentially invented, but its fresh-out-the-box sheen has long since faded. If there had to be another single from Circus, couldn't they have gone with 'Unusual You' or 'Kill The Lights' instead?